Merge pull request #3561 from dreampiggy/bugfix/macOS_limitBytes_anim…

…atedImageRep

Fix macOS bug that SDImageCoderDecodeScaleDownLimitBytes still use the AnimatedImageRep and beyond the byte limit

SDWebImage/Core/SDImageCoder.h

@@ -83,6 +83,7 @@ FOUNDATION_EXPORT SDImageCoderOption _Nonnull const SDImageCoderDecodeUseLazyDec
  3. If the `framePixelSize < originalImagePixelSize`, then do thumbnail decoding (see `SDImageCoderDecodeThumbnailPixelSize`) use the `framePixelSize` and `preseveAspectRatio = YES`
  4. Else, use the full pixel decoding (small than limit bytes)
  5. Whatever result, this does not effect the animated/static behavior of image. So even if you set `limitBytes = 1 && frameCount = 100`, we will stll create animated image with each frame `1x1` pixel size.
+ @note You can use the logic from `+[SDImageCoder scaledSizeWithImageSize:limitBytes:bytesPerPixel:frameCount:]`
  @note This option has higher priority than `.decodeThumbnailPixelSize`
  */
 FOUNDATION_EXPORT SDImageCoderOption _Nonnull const SDImageCoderDecodeScaleDownLimitBytes;

SDWebImage/Core/SDImageCoderHelper.h

@@ -104,6 +104,12 @@ typedef NS_ENUM(NSUInteger, SDImageCoderDecodeSolution) {
  */
 + (CGSize)scaledSizeWithImageSize:(CGSize)imageSize scaleSize:(CGSize)scaleSize preserveAspectRatio:(BOOL)preserveAspectRatio shouldScaleUp:(BOOL)shouldScaleUp;
 
+/// Calculate the limited image size with the bytes, when using `SDImageCoderDecodeScaleDownLimitBytes`. This preserve aspect ratio and never scale up
+/// @param imageSize The image size (in pixel or point defined by caller)
+/// @param limitBytes The limit bytes
+/// @param bytesPerPixel The bytes per pixel
+/// @param frameCount The image frame count, 0 means 1 frame as well
++ (CGSize)scaledSizeWithImageSize:(CGSize)imageSize limitBytes:(NSUInteger)limitBytes bytesPerPixel:(NSUInteger)bytesPerPixel frameCount:(NSUInteger)frameCount;
 /**
  Return the decoded image by the provided image. This one unlike `CGImageCreateDecoded:`, will not decode the image which contains alpha channel or animated image. On iOS 15+, this may use `UIImage.preparingForDisplay()` to use CMPhoto for better performance than the old solution.
  @param image The image to be decoded

SDWebImage/Core/SDImageCoderHelper.m

@@ -428,6 +428,19 @@ + (CGSize)scaledSizeWithImageSize:(CGSize)imageSize scaleSize:(CGSize)scaleSize
     return CGSizeMake(resultWidth, resultHeight);
 }
 
++ (CGSize)scaledSizeWithImageSize:(CGSize)imageSize limitBytes:(NSUInteger)limitBytes bytesPerPixel:(NSUInteger)bytesPerPixel frameCount:(NSUInteger)frameCount {
+    if (CGSizeEqualToSize(imageSize, CGSizeZero)) return CGSizeMake(1, 1);
+    NSUInteger totalFramePixelSize = limitBytes / bytesPerPixel / (frameCount ?: 1);
+    CGFloat ratio = imageSize.height / imageSize.width;
+    CGFloat width = sqrt(totalFramePixelSize / ratio);
+    CGFloat height = width * ratio;
+    width = MAX(1, floor(width));
+    height = MAX(1, floor(height));
+    CGSize size = CGSizeMake(width, height);
+
+    return size;
+}
+
 + (UIImage *)decodedImageWithImage:(UIImage *)image {
     if (![self shouldDecodeImage:image]) {
         return image;

SDWebImage/Core/SDImageIOAnimatedCoder.m

@@ -47,19 +47,6 @@ static CGImageRef __nullable SDCGImageCreateCopy(CGImageRef cg_nullable image) {
     return newImage;
 }
 
-static inline CGSize SDCalculateScaleDownPixelSize(NSUInteger limitBytes, CGSize originalSize, NSUInteger frameCount, NSUInteger bytesPerPixel) {
-    if (CGSizeEqualToSize(originalSize, CGSizeZero)) return CGSizeMake(1, 1);
-    NSUInteger totalFramePixelSize = limitBytes / bytesPerPixel / (frameCount ?: 1);
-    CGFloat ratio = originalSize.height / originalSize.width;
-    CGFloat width = sqrt(totalFramePixelSize / ratio);
-    CGFloat height = width * ratio;
-    width = MAX(1, floor(width));
-    height = MAX(1, floor(height));
-    CGSize size = CGSizeMake(width, height);
-
-    return size;
-}
-
 @interface SDImageIOCoderFrame : NSObject
 
 @property (nonatomic, assign) NSUInteger index; // Frame index (zero based)
@@ -384,10 +371,16 @@ - (UIImage *)decodedImageWithData:(NSData *)data options:(nullable SDImageCoderO
         lazyDecode = lazyDecodeValue.boolValue;
     }
 
+    NSUInteger limitBytes = 0;
+    NSNumber *limitBytesValue = options[SDImageCoderDecodeScaleDownLimitBytes];
+    if (limitBytesValue != nil) {
+        limitBytes = limitBytesValue.unsignedIntegerValue;
+    }
+
 #if SD_MAC
     // If don't use thumbnail, prefers the built-in generation of frames (GIF/APNG)
     // Which decode frames in time and reduce memory usage
-    if (thumbnailSize.width == 0 || thumbnailSize.height == 0) {
+    if (limitBytes == 0 && (thumbnailSize.width == 0 || thumbnailSize.height == 0)) {
         SDAnimatedImageRep *imageRep = [[SDAnimatedImageRep alloc] initWithData:data];
         if (imageRep) {
             NSSize size = NSMakeSize(imageRep.pixelsWide / scale, imageRep.pixelsHigh / scale);
@@ -432,11 +425,6 @@ - (UIImage *)decodedImageWithData:(NSData *)data options:(nullable SDImageCoderO
     size_t frameCount = CGImageSourceGetCount(source);
     UIImage *animatedImage;
 
-    NSUInteger limitBytes = 0;
-    NSNumber *limitBytesValue = options[SDImageCoderDecodeScaleDownLimitBytes];
-    if (limitBytesValue != nil) {
-        limitBytes = limitBytesValue.unsignedIntegerValue;
-    }
     // Parse the image properties
     NSDictionary *properties = (__bridge_transfer NSDictionary *)CGImageSourceCopyPropertiesAtIndex(source, 0, NULL);
     size_t width = [properties[(__bridge NSString *)kCGImagePropertyPixelWidth] doubleValue];
@@ -445,7 +433,7 @@ - (UIImage *)decodedImageWithData:(NSData *)data options:(nullable SDImageCoderO
     if (limitBytes > 0) {
         // Hack since ImageIO public API (not CGImageDecompressor/CMPhoto) always return back RGBA8888 CGImage
         CGSize imageSize = CGSizeMake(width, height);
-        CGSize framePixelSize = SDCalculateScaleDownPixelSize(limitBytes, imageSize, frameCount, 4);
+        CGSize framePixelSize = [SDImageCoderHelper scaledSizeWithImageSize:imageSize limitBytes:limitBytes bytesPerPixel:4 frameCount:frameCount];
         // Override thumbnail size
         thumbnailSize = framePixelSize;
         preserveAspectRatio = YES;
@@ -568,7 +556,7 @@ - (void)updateIncrementalData:(NSData *)data finished:(BOOL)finished {
     if (_limitBytes > 0) {
         // Hack since ImageIO public API (not CGImageDecompressor/CMPhoto) always return back RGBA8888 CGImage
         CGSize imageSize = CGSizeMake(_width, _height);
-        CGSize framePixelSize = SDCalculateScaleDownPixelSize(_limitBytes, imageSize, _frameCount, 4);
+        CGSize framePixelSize = [SDImageCoderHelper scaledSizeWithImageSize:imageSize limitBytes:_limitBytes bytesPerPixel:4 frameCount:_frameCount];
         // Override thumbnail size
         _thumbnailSize = framePixelSize;
         _preserveAspectRatio = YES;
@@ -773,7 +761,7 @@ - (nullable instancetype)initWithAnimatedImageData:(nullable NSData *)data optio
         if (_limitBytes > 0) {
             // Hack since ImageIO public API (not CGImageDecompressor/CMPhoto) always return back RGBA8888 CGImage
             CGSize imageSize = CGSizeMake(_width, _height);
-            CGSize framePixelSize = SDCalculateScaleDownPixelSize(_limitBytes, imageSize, _frameCount, 4);
+            CGSize framePixelSize = [SDImageCoderHelper scaledSizeWithImageSize:imageSize limitBytes:_limitBytes bytesPerPixel:4 frameCount:_frameCount];
             // Override thumbnail size
             _thumbnailSize = framePixelSize;
             _preserveAspectRatio = YES;